Doug Hall also touched down for Gregor Townsend’s men on a night when returning captain Al Kellock made his 150th appearance for his cub.

Scrum-half Henry Pyrgos added all the other points on what was a satisfactory night for the league leaders, despite their failure to bag a bonus point.

Zebre came into this one full of confidence having registered their first-ever league win against Cardiff last week, and they proved a tough nut to crack for the Warriors, especially during the first half.

With nine changes to their starting XV, Glasgow struggled to reach the intensity shown against Leinster in their previous fixture, and rarely got out of third gear during a rather listless first half.

That said, they did go down the tunnel at half-time leading 10-3, courtesy of a penalty and a conversion by Pyrgos, and a stunning team try eventually finished off by McGuigan in the 27th minute.

The try, when it came, was straight off the training paddock. A solid scrum on halfway saw the ball shifted into the arms of centre Gabriel Ascarate, whose inside switch put Alex Dunbar away past the first line of defence.

From there, the Stirling man drew the fullback before finding McGuigan in support, and the Namibian-born winger sprinted home without a hand being placed on him.

Apart from that, there wasn’t a whole lot to report from the first half.

Glasgow coughed up three promising attacking opportunities by infringing at scrum time, where Zebre seemed to hold sway. They also botched a five-metre lineout.

Glasgow’s inability to build phases or sustain pressure was perhaps their most glaring deficiency of the first half.

Against that, their defence was operating to its usual high standards, and Zebre never looked like scoring a try, despite breaking the line close to the ruck on a number of occasions.

The best they had to show for their first-half efforts was a 32nd-minute penalty by Luciano Orquera.

Zebre prop Salvatore Perugini then found himself in the bin for not releasing after the tackle, but Glasgow failed to take advantage during the remainder of the first half.

However, they did make their numerical advantage count in the first minute of the second half, just before Perugini’s return, with Hall crashing over for try number two, again a team effort after some fine continuity play between backs and forwards.

On this occasion, they managed to work four-on-two overlap in the corner, and there was the 32-year-old in perfect position to claim his first try of the season.

Pyrgos’s conversion took the score out to 17-3 for Glasgow, with the game now seemingly beyond Zebre. To their credit, though, they regrouped, and made Glasgow work hard to protect their try line.

But the Warriors defended with assurance before flexing their muscles ever so slightly during the final half-hour.

McGuigan claimed his second try of the night on 55 minutes, this time the result of some neat interplay among the three-quarter division.

Ascarate was making his first start since his summer arrival, and the more the game wore on, the more influential he became, with his clever lines of running and smart range of passing.

Sean Maitland was also making his first appearance of the season after his Lions involvement, whilst Niko Matawalu also made his return from injury off the bench.

Jonny Gray was sent to the bin in the 70th minute after one discretion too many and, with a one-man deficit, Glasgow’s defence eventually buckled two minutes later when Zebre No 8 Samuela Vunisa barged over.

The try was the first that Glasgow had conceded this season, and they conceded another almost immediately after when winger Leonardo Sarto found himself in space down the left flank.

Townsend said afterwards: “You have to work hard for any win in this league, so we’ll take the four points and move on. But the players are disappointed with the level of performance tonight, and especially that of the last 20 minutes or so.

“Maybe we relaxed, we certainly didn’t display the same accuracy or intensity of our earlier games. All credit to Zebre, they scored a couple of good tries. And, had they got the ball in the end, they might have had the opportunity to claim a draw.

“But we’re delighted to get the win. We know we were a bit off-key tonight but we kept the momentum going and that’s the most important thing.”